My husband and his family have used raw potato juice for acid reflux and gastritis for years. And it has worked for everyone we've recommended it to. It is not an everyday kind of treatment, they only use it when they finally abuse their tummies too much with spicy or greasy diets on a long term. Then they use it for a week or so and they go back to normal. It consists of throwing a small raw potato in the juicer along with some carrots, for taste. Drink it right away or it will darken and not taste as good (I guess it also loses some properties with oxidation). One of these juices every morning for a week seems to do the trick.
BTW, My 83 yr old mother-in-law can eat ANYTHING (and I'm talking greasy, spicy mexican food here) and be fine. Thank you for this site, I plan to contribute feedback for many of your wonderful remedies.